Toxicology E3R Practice Exam

Steam distillation uses water vapor to extract essential oils. In this method, plant material is exposed to steam, which carries the volatile oil components into the vapor phase. Because the essential oils vaporize with the steam at temperatures lower than their normal boiling points, heat damage to sensitive compounds is minimized. The steam-oil mixture then condenses; the oil and water separate because essential oils are immiscible with water, allowing the oil to be collected cleanly. This approach is particularly useful for delicate aromatic compounds that might degrade with direct heating.

Other methods don’t rely on water vapor for extraction: cold pressing uses mechanical force to release oils without steam; solvent extraction relies on organic solvents to dissolve oils; aerosolization refers to dispersing substances as aerosols rather than extracting oils from plant material.